1. Field of the Invention
The present invention relates to vision systems, e.g., as deployed on a vehicle. In particular, this invention relates to detecting imminent collisions using stereo vision.
2. Description of the Related Art
Significant interest exists in the automotive industry for systems that detect imminent collisions in time to avoid that collision or to mitigate its damage. Collision avoidance systems typically must detect the presence of potential threats, determine their speed and trajectory, and assess their collision threat. Prior art collision avoidance systems have used radar to determine the range and closing speed of potential threats. However, affordable radar systems usually lack the required spatial resolution to reliably and accurately determine the size and the location of potential threats.
Since stereo vision can provide the high spatial resolution required to identify potential threats, stereo vision has been proposed for use in collision detection and avoidance systems. For example, U.S. patent application Ser. No. 10/461,699, filed on Jun. 13, 2003 and entitled “VEHICULAR VISION SYSTEM,” which is hereby incorporated by reference in its entirety, discloses detecting and classifying objects (potential threats) using disparity images, depth maps, and template matching. While the teachings of U.S. patent application Ser. No. 10/461,699 are highly useful, its methods of detecting potential threats are not optimal in all applications.
Therefore, there is a need in the art for new techniques of using stereo vision for collision detection and avoidance.